US3736393A - Positive retained actuation switch - Google Patents

Positive retained actuation switch Download PDF

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Publication number
US3736393A
US3736393A US00207365A US3736393DA US3736393A US 3736393 A US3736393 A US 3736393A US 00207365 A US00207365 A US 00207365A US 3736393D A US3736393D A US 3736393DA US 3736393 A US3736393 A US 3736393A
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US
United States
Prior art keywords
cylindrical
chamber
stem
prongs
piston
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US00207365A
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English (en)
Inventor
M Apple
H Hughes
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Bendix Corp
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Bendix Corp
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Filing date
Publication date
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Publication of US3736393A publication Critical patent/US3736393A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
    • B60T17/18—Safety devices; Monitoring
    • B60T17/22—Devices for monitoring or checking brake systems; Signal devices
    • B60T17/226—Devices for monitoring or checking brake systems; Signal devices using devices being responsive to the difference between the fluid pressions in conduits of multiple braking systems
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/38—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow actuated by piston and cylinder

Definitions

  • the land section is [21] Appl 207365 flanked by annular ramps leading to a cylindrical sec tion on the stern.
  • a non-conductive body having a Cl 200/153 200/159 A cylindrical bore is secured to the housing.
  • a plunger Int. member with an axial projection is located in the Field Of Search D, 61.19, cylindrical bore and extends into the entral cavity to 200/153 153 159 159 A contact the land section on the stem.
  • a clip having a plurality of prongs is attached to the rear of the axial Refel'eflces Cited projection.
  • a pressure differential between the first UNITED STATES PATENTS and second chambers will move the first and second pistons toward the lower pressure chamber permlttmg 3,606,487 9/1971 Kersting ..200/82 D X the axial projection to move off the land section down 3,637,963 l/l972 Wellman ..200/82 D the ramp to the cylindrical section on the stem.
  • a pressure differential will occur causing the plunger to slide up a ramp and close an electrical contact to-initiate a signal for warning the operator of a malfunction in the brake system.
  • the plunger will again slide down the ramp to break the electrical circuit.
  • a malfunction signal is only activated while the brakes are applied. Since it is likely that the vehicle operator might overlook the signal if the brakes are briefly applied, it is desirable to have a warning switch which will continue to operate continually after an initial failure has activated the switch until the failure is corrected.
  • FIG. 1 is a schematic view of a differentially operated fluid pressure switch means in a dual hydraulic braking system of an automotive vehicle.
  • FIG. 2 is a sectional view of the fluid pressure switch means with equalizing hydraulic pressure in both the front and rear brake systems with an electrical contact resiliently held on a non-conductive sleeveto interrupt electrical continuity between an indicator and the switch.
  • FIG. 3 is a sectional view of the electrical contact of FIG. 2 which is resiliently held on an electrical terminal during and after an initial pressure differential is present in the dual hydraulic braking system.
  • FIG. 4 is a sectional view of the preferred embodiment of the resiliently controlled contact means for transmission of an operation signal indicating a pressure differential in the dual braking system in an interrupted position.
  • FIG. 5 is a sectional view of a contact means of FIG. 4 in the activated position.
  • a master cylinder 10 of a type fully described in copending US. application Ser. No. 204,550, filed Dec. 3, l97l, and incorporated herein by reference has a primary pressurizing conduit 12 leading to an inlet port 14 and a secondary pressurizing conduit 18 leading to a second inlet port 20 of a pressure warning switch means 16.
  • Fluid pressure in master cylinder 10 is developed by an operator initially depressing pedal 22 which causes a first hydraulic fluid pressure to be communicated through inlet port 14 via a metering valve means 24, see FIG. 2, (of a type fully described in US. Pat. No. 3,603,648 and incorporated herein by reference) positioned in the housing 26 of the warning switch 16.
  • the metering valve 24 is connected to the front wheel disc brakes 28 through outlet ports 30 in the housing 26. Further depression of pedal 22 causes a second hydraulic fluid pressure to be transmitted through the second inlet port 20 to the cylindrical cavity 32 in housing 26 and past outlet port 34 to the rear wheel drum brakes 36.
  • warning switch 16 With equalizing pressures in conduits I2 and 18, the warning switch 16 is inactivated and the electrical continuity between the grounded housing 26 and indicator light 38 interrupted. With a failure in either the connection between conduit 12'and the front wheel disc brakes 28 or the connection between conduit 18 and the rear wheel drum brakes 36, a pressure differential will be sensed by the warning switch means 16. Upon sensing a pressure differential, warning switch means 16 establishes electrical continuity between ground 40 through the housing 26 to cause indicator light 38 to be energized by electrical power source 42. Electrical continuity through the warning switch means 16' will continue until an equalizing pressure is restored in conduits 12 and 18. y
  • the warning switch means 16 shown in FIG. 2 consists of housing 26 having a cylindrical cavity 32 therethrough.
  • the cylindrical cavity 32 is connected to the first inlet port 14 by passage 44 and the second inlet port 20 by passage 46.
  • a first piston means 48 has a cylindrical section 50 with agroove 52 for holding seal 54 is located inthe cylindrical cavity 32.
  • the cylindrical section 50 is located adjacent the first inlet port passage 44.
  • the forward face 56 of the cylindrical section 50 forms a first chamber 58 with cap 60.
  • Cap 60 retains the end 62 of the metering valve means 24 located in the first chamber 58.
  • the first chamber 58 has outlet ports 30 going to the front wheel disc brakes 28.
  • a second piston means 60 has a cylindrical section 62 with a rib 64.
  • a seal 66 located between discs 68 and 70 which surround the cylindricalsection 62 prevents hydraulic fluid under pressure from being communicated from a second chamber 72 into a control chamber 74 between the first and second piston means 48 and 60.
  • the second chamber 72 is formed by the forward face 76 of the second piston means 60 and plug 78 which seals the cylindrical cavity 32.
  • Plug 78 has a central passage which permits communication of pressurized fluid from the second chamber'74 through outlet 34 to the rear wheel drum brakes 36.
  • the first piston 48 and second piston 60 are rigidly connected to each other by a stem means 80.
  • the stem means 80 has a first cylindrical section 82 and a second cylindrical section 84 adjacent a first annular ramp 86 and a second annular ramp 88 leading to a first edge 90 and a second edge 92 of a land section 94, respectively.
  • An electrically non-conductive body or fitting 95 is secured in opening 96 of housing 26 by threads 98.
  • the body 95 has a stepped cylindrical bore 100 along its central axis.
  • a sleeve 102 which is concentric with the central axis of the stepped bore extends into a switching chamber 104 formed by non-conductive body 95 and the housing 26 at the bottom of opening 96.
  • An electrical terminal 106 has one end 108 located in the switching chamber 104 and another end 110 which extends into a connection chamber 112 of the non-conductive body 95.
  • End 108 has a diameter substantially equal to sleeve 102 and is held in a tight abutting relationship therewith along the central axis of bore 100 by anchor 1 l3 spaced along the terminal 106.
  • the anchors 113 are embedded in the non-conductive body 95. End llis connected to indicator 28 by electrical lead 115.
  • a plunger means 114 includes a cylindrical member 116 which has a diameter substantially equal to the section of the stepped bore 100.
  • the cylindrical member 116 is retained in the bore 100 by arcuate rib 118 and includes an axial projection 120 which extends through an opening 123 of housing 26 and into the second chamber 74 of the cylindrical cavity 32.
  • the axial projection 120 has a spherical head 122 which is brought into contact with the stem means 80 by a resilient means 124.
  • the resilient means 124 is located in the switching chamber 104 with one end 126 against a shoulder 128 of the non-conductive body 94 and the other end 130 on the rear face 132 of the cylindrical body 116.
  • Contact clip means 134 has a base 136 which is centra'lly positioned on the rear face 132 of the cylindrical body 116 by rivet 138.
  • a plurality of prong members 140 integral with the base 136 extend rearwardly on an inward angle for a predetermined distance to form a contact point 142.
  • Each of the prong members has an arcuate segment 144 extending radially outwardly from the contact point 142.
  • Resilient means 124 will hold the second piston means 60 against stop 146 until the hydraulic pressure in chamber 72 acting on face 76 and disc 70 is great enough to overcome the hydraulic pressure in chamber 58 acting on face 56 and the resultant from the biasing force of the resilient means 124.
  • stem means 80 will slide in bore 32, causing the spherical head 122 to move the arcuate ramp 86 until positioned on land 94.
  • the contact points 142 of the prongs will slide off the end 108 of the electrical terminal onto the nonconductive sleeve 102, causing an electrical continuity between the housing 26 and the electrical terminal 106 to be broken. With electrical continuity broken, indicator 38 is deactivated informing the operator that equalized braking pressures are present in the first and second chambers 58 and 72.
  • the resilient means 124 will hold stem means 80 in this stationary position permitting continual electrical energization of the indicator 38 until sufficient hydraulic pressure in chamber 58 acting on face 56, which has a slightly larger diameter than face 76, to reposition land 94 under the spherical head 122.
  • FIG. 4 DESCRIPTION OF THE PREFERRED EMBODIMENT
  • the invention as shown in FIG. 4 is essentiaLly the same as that of FIG. 2 with the exception of the means for establishing electrical continuity between terminal 106 and housing 26. It should be noted that parts that are identical to those used in FIG. 2 are given the same reference numeral since they perform the same function in this embodiment of FIG. 4.
  • a rearward axial projection 250 is secured to the rear of the cylindrical body or disc 116 and extends into the switching chamber 104 toward end 108 of the electrical terminal 106.
  • a disc 252 having its periphery abutting shoulder 254 of the non-conductive body 95 has a plurality of prongs 256 extending inwardly on an angle for a predetermined distance. Each of the prongs has a contact point 258 from which an arcuate section 260 extends radially outward.
  • Resilient means 124 will hold the spherical head 122 in the cylindrical section of the stem means 80 until an equalizing pressure is present in chambers 58 and 70 at which time the spherical head will be moved up the arcuate ramp to the land section 94.
  • head 262 will engage and spread prongs 256 moving contacts 258 out of engagement with end 108 interrupting the operational signal to the indicator light 38.
  • Switch means responsive to a pressure differential between a first and second hydraulically operated system, said switch means comprising:
  • a housing having a cylindrical cavity therein with a first inlet port and a second inlet port connected to separate fluid pressurizing means;
  • first piston means located in said cylindrical cavity adjacent said first inlet port for forming a first chamber in the cylindrical cavity with the housing, said first chamber having a first outlet port connected to said first hydraulically operated system;
  • second piston means located in said cylindrical cavity adjacent said second inlet port for forming a second chamber in the cylindrical cavity with the housing, said second chamber having a second outlet port connected to said second hydraulically operated system;
  • stem means located in said cylindrical cavity for connecting said-first piston means to said second piston means, said stem means being ofa smaller diameter than said first and second piston means, said stem means having a land section with a diameter substantially equal to said first and second piston means, said stem means having a first ramp going from a first cylindrical section of the stem to one edge of said land section and a second ramp going from a second cylindrical section of the stem to the other edge of said land section;
  • plunger means located in said cylindrical bore having an axial projection with a spherical head on one end and a cylindrical head on the other end, said spherical head extending into said cylindrical cavity to contact said land section on said stem means when the hydraulic pressure in the first and second chamber acting on the first and second piston is substantially equal;
  • first disc surrounding said axial projection, said first disc having a diameter substantially equal to said cylindrical bore, said axial projection being maintained in axial alignment in said cylindrical bore by the engagement of the periphery of said first disc with said cylindrical bore;
  • clip means having a second disc whose periphery abuts a shoulder in said cylindrical bore, said second disc having a plurality of prongs extending inwardly on an angle from the periphery, each of said prongs having an arcuate section extending radially outward at a predetermined distance from said disc;
  • resilient means located in said cylinder bore between said first and second discs for biasing said spherical head of the plunger means into contact with said stem means and said second disc against said shoulder, said cylindrical head of the plunger means engaging said prongs when said spherical head is on said land section causing the prongs to pivot.
  • said cylindrical head moving out of engagement with said prongs as the spherical head moves down the arcuate ramp in response to a pressure differential between said first and second chambers causing the first and second piston means to slide in said cavity'permitting said prongs to contact said one end of the electrical terminal, said resilient means aiding said pressure differential in sliding said piston means in said cylindrical cavity when said spherical head is on one of said first and second ramps, said resilient means maintainingsaid clip means in contact with said electrical terminal and continually transmitting said operational signal therethrough until substantially equal pressures in the first and second chamber reposition said spherical head on said land section and thereby break the electrical continuity between the housing and the electrical terminal.
  • anchor means fixed in said electrical non-conductive body for holding the cylindrical head stationary.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
  • Hydraulic Control Valves For Brake Systems (AREA)
  • Braking Arrangements (AREA)
US00207365A 1971-12-13 1971-12-13 Positive retained actuation switch Expired - Lifetime US3736393A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US20736571A 1971-12-13 1971-12-13

Publications (1)

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US3736393A true US3736393A (en) 1973-05-29

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Application Number Title Priority Date Filing Date
US00207365A Expired - Lifetime US3736393A (en) 1971-12-13 1971-12-13 Positive retained actuation switch

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US (1) US3736393A (es)
JP (1) JPS4865371A (es)
CA (1) CA952948A (es)
FR (1) FR2163449B1 (es)
GB (1) GB1357839A (es)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50160665A (es) * 1974-05-17 1975-12-26
US5046313A (en) * 1989-07-27 1991-09-10 Allied-Signal Inc. Master cylinder with fluid level and pressure failure detection

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5291473U (es) * 1975-12-29 1977-07-08
FR2501605A1 (fr) * 1981-03-16 1982-09-17 Dba Detecteur de desequilibre de pression

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2060377A (en) * 1933-08-01 1936-11-10 Glenn D Knodle Motor vehicle rear end spotlight switch
GB578032A (en) * 1944-08-02 1946-06-12 Eustace Russell Booth Improvements in push-button electric switches
US3448230A (en) * 1967-03-28 1969-06-03 Wagner Electric Corp Control valve and system
US3606487A (en) * 1969-11-04 1971-09-20 Wagner Electric Corp Control valve
US3622934A (en) * 1969-05-30 1971-11-23 Matsushita Electric Ind Co Ltd Variable resistor of sliding type with switch activated by slider
US3637963A (en) * 1970-03-02 1972-01-25 Weatherhead Co Brake warning switch with bypass

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3427582A (en) * 1965-10-07 1969-02-11 Bendix Corp Failure indicating apparatus for a split brake system
US3542438A (en) * 1969-04-07 1970-11-24 Wagner Electric Corp Control valve

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2060377A (en) * 1933-08-01 1936-11-10 Glenn D Knodle Motor vehicle rear end spotlight switch
GB578032A (en) * 1944-08-02 1946-06-12 Eustace Russell Booth Improvements in push-button electric switches
US3448230A (en) * 1967-03-28 1969-06-03 Wagner Electric Corp Control valve and system
US3622934A (en) * 1969-05-30 1971-11-23 Matsushita Electric Ind Co Ltd Variable resistor of sliding type with switch activated by slider
US3606487A (en) * 1969-11-04 1971-09-20 Wagner Electric Corp Control valve
US3637963A (en) * 1970-03-02 1972-01-25 Weatherhead Co Brake warning switch with bypass

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50160665A (es) * 1974-05-17 1975-12-26
JPS6030583B2 (ja) * 1974-05-17 1985-07-17 ガーリング・リミテツド ブレ−キ装置用圧力制御弁
US5046313A (en) * 1989-07-27 1991-09-10 Allied-Signal Inc. Master cylinder with fluid level and pressure failure detection

Also Published As

Publication number Publication date
FR2163449A1 (es) 1973-07-27
JPS4865371A (es) 1973-09-08
GB1357839A (en) 1974-06-26
CA952948A (en) 1974-08-13
FR2163449B1 (es) 1976-06-04

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